Mining the past for clues on climate change

Between 1907 and 1961, the professor and botanist for what eventually became North Dakota State University traveled the state, documenting everything he could find and compiling diligent records on how plants responded to differences in temperature and weather.

Now, as scientists study how global climate change affects plant life, his century-old notes have turned into a treasure trove of data.

“He had a window into what plants were responding to,” said Steven Travers, an assistant professor of biology at NDSU. “He knew certain species were tracking temperature much better than other ones.”

Travers spent much of the past few years digging into Stevens’ data as part of a sprawling study on how shifts in temperature affect when plants flower. The research, which involved 22 institutions on four continents, found that flowering and leafing times respond to change more quickly than previously thought.

An increase of 1 degree Celsius can push flowering times forward five or six days, Travers said. As the world gets warmer – spurred by factors natural or otherwise – spring comes earlier, and late-summer plants wait longer.

That can throw off the delicate balance of power in ecosystems, giving some plants – particularly invasive species – a leg up and leaving others behind.

“That’s one of the things that we’re curious about, is who’s doing better and who’s doing worse,” Travers said. “Is there a consequence to coming up earlier? Are they getting visited less by pollinators?”

The study was recently published in the prominent scientific journal Nature. Travers said Stevens’ data offered an invaluable snapshot of the past.

“We need to know what these exact places were like 100 years ago. It’s too late to start collecting that now,” he said.

Research is still ongoing, and Travers and his colleagues are still looking for caches of historical data, from handwritten notes of bygone botanists to shoeboxes of flowers grandma may have left in the closet.

He said the long-term outlook is not yet clear.

“One question is, ‘How far it is going to go?’ ” he said, adding that if the current direction holds, “we’re basically going to end up like Kansas in some time period.”

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